1. Field of the Invention
This invention relates to a prosthetic apparatus, and, more particularly, to a shock absorber apparatus for a prosthetic leg for both axial shock absorption and relative torsional or rotational movement.
2. Description of the Prior Art
There are generally two problems with prosthetic leg apparatus including the inability to absorb shocks and the inability to rotate. Shock absorption increases the natural feel and comfort of the leg, and the rotation of varying degrees allows a more ordinary turn while walking, or allows a combination of pivoting action required for sports activities of different types.
An effort to overcome the problems is shown in U.S. Pat. No. 5,800,562, dated Sep. 1, 1998, the inventor of which is co-inventor herein. The ""562 patent utilizes elastomeric elements and a spring element to provide both vertical and torsional movement. The elastomeric elements provide vertical shock absorber action and, with the spring element, also allow a degree of rotational movement and shock absorber action.
Another example of the prior art is found in co-pending application, Ser. No. 09/389,735, filed Sep. 7, 1999 the inventor of which is co-inventor herein. The ""562 patent may be considered as the first generation apparatus, while the ""735 application may be considered the second generation apparatus, with the present invention as the third generation, each of which utilizes an elastomeric element for shock absorbing capabilities and, with other elements, for torsion relative rotation or movement as well. However, the present apparatus utilizes an elastomeric element for both shock absorbency and torsional resistance or movement, without the need for other elements.
The invention described and claimed herein comprises a shock absorber for a prosthetic leg utilizing an elastomeric element which also offers torsional resistance to allow the user of the prosthetic apparatus to rotate, thus simulating the natural movement of a leg and ankle. The elastomeric element is secured between a lower pylon element and an upper pyramid adaptor element and is disposed on the outside of both elements. The elastomeric element is the only fixed connection between the pylon and the pyramid adaptor. The extent of the cushioning or shock absorbency and the extent of the torsional resistance may be varied by different types of elastomeric elements and by the location on the pylon on which the elastomeric element is secured.
Among the objects of the present invention are the following:
To provide new and useful shock absorber apparatus for a prosthetic leg;
To provide new and useful prosthetic leg apparatus having both longitudinal or axial shock absorber characteristics and rotational pivoting characteristics;
To provide an elastomeric element disposed outside of a pylon and secured to a pylon and a pyramid adaptor;
To provide new and useful prosthetic apparatus for absorbing axial shocks and for permitting twisting or torsional relative movement;
To provide new and useful prosthetic apparatus including a pyramid adaptor and a pylon secured together by an elastomeric element; and
To provide new and useful elastomeric elements usable in a prosthetic apparatus and having different torsional and longitudinal shock absorbing characteristics.